1. Field of the Invention
The present invention relates to a semiconductor package which accommodates a semiconductor device and a semiconductor package assembly assembled with the semiconductor package.
2. Description of the Related Art
A semiconductor device typified by, for example, an integrated circuit is distributed and used in a state that the semiconductor device together with a basic circuit including the semiconductor device has been accommodated in a package for assuring its performance. The semiconductor package includes a package main body which accommodates the basic circuit including the semiconductor device, and a plurality of external connection terminal members which is connected to the basic circuit accommodated in the package main body and which protrudes outside the package main body.
The semiconductor package is placed at a predetermined position on a circuit board on which an electrical circuit to be used with the basic circuit accommodated in the semiconductor package is configured, and the plurality of external connection terminal members is electrically connected to a plurality of external connection terminals of the electrical circuit by electrical connection elements such as, for example, solder.
The semiconductor device generates heat with its operation. The semiconductor device is relatively weak against heat, and when a temperature of the semiconductor device reaches a predetermined temperature or higher, the operation of the semiconductor device becomes unstable or becomes inoperative.
In a conventional semiconductor package, the heat generated by the semiconductor device is radiated from the package main body to an atmosphere surrounding the package main body, so that the temperature of the semiconductor device is maintained lower than the predetermined temperature. In recent years, a heat radiation amount from the semiconductor device increases with an improvement of the performance of the semiconductor device, so that a plurality of cooling fins is provided on an outer surface of the package main body or the atmosphere surrounding the package main body is further blown to the cooling fins by a blower.
Recently, a semiconductor device which has a higher performance than that of the conventional one but which uses, for example, gallium nitride (GaN) easily breakable by uneven distribution of heat is also used. A cooling structure for a semiconductor package accommodating such a semiconductor device as described above is disclosed in, for example, Japanese Utility Model Application KOKAI Publication No. 05-4498.
In this cooling structure, a package main body provided on its outer surface with a plurality of cooling fins is immersed in circulating liquid coolant. The above-mentioned outer surface is raised from a central portion toward a peripheral portion, and the above-mentioned circulating liquid coolant is applied toward the central portion. Since the outer surface is raised as described above, an area of the outer surface is increased and turbulence is produced in the liquid coolant flowing from the central portion to the peripheral portion along the outer surface. As a result, a contacting time of the liquid coolant with the outer surface (heat exchange time) is increased.
In the conventional semiconductor package with the above-mentioned conventional cooling structure using liquid coolant, the liquid coolant is flowing along the outer surface of the package main body positioned far from the semiconductor device accommodated in the inner space of the package main body. Therefore, in a case that an amount of heat generated from the semiconductor device further increases with further performance improvement of the semiconductor device, it is surely anticipated that it becomes difficult to control temperature rise of the semiconductor device within a predetermined range by the above-mentioned conventional cooling structure. Further, in the above-mentioned conventional semiconductor package with the above-mentioned conventional cooling structure, the plurality of cooling fins provided on the outer surface of the package main body increases outer dimensions of the whole conventional semiconductor package.